1. Field of the Invention
This invention relates to a novel diesel engine crankcase lubricating composition which exhibits improved resistance to corrosion, oxidation and hazing. More particularly, this invention relates to a novel corrosion, oxidation and haze resistant diesel engine crankcase lubricating composition comprising a major amount of a hydrocarbon lubricating oil and a minor amount of the reaction product of a prescribed anhydride compound, a hydrocarbon-substituted mono primary amine or ether amine, and a nitrogen-containing heterocyclic azole or polyalkylene polyamine compound. The instant invention is particularly useful as a lubricant in large diesel engines such as marine and railway diesel engines.
As is well known to those skilled in the art, lubricating oils must be characterized by resistance to oxidation, by freedom from haze, and by rust and corrosion inhibition. Since the oils used as lubricants in the crankcases of large diesel engines, such as marine and railway diesel engines, are subject to unique conditions of operation, special attention must be directed to the potential problems which are to be encountered. These oils are typically formulated to contain anti-wear additives, oxidation inhibitors, demulsifying agents, rust-inhibitors, etc. Illustrative oils may include those of U.S. Pat. No. 4,358,386 or U.S. Pat. No. 4,375,418, inter alia.
In particular, it has been found that conventional rust-inhibited marine diesel engine crankcase lubricants tend to have haze problems caused by the presence of the rust inhibitor component. This is undesirable because it masks or interferes with determination of the presence in the lubricant of undesirable components including decomposition products, water, or solid particles.
In addition, the advent of new, more fuel efficient railway diesel engines has put a greater demand on the oxidation resistance of railway diesel lubricants. Oxidized lubricants lead to increased corrosive attack of engine metal surfaces; consequently, lubricants employed in newer railway diesel engines must be changed more frequently to prevent such corrosive attack.
It is an object of this invention to provide a novel diesel engine lubricant. It is another object to provide a novel lubricant composition, suitable for use in large marine and railway diesel engines, characterized by its resistance to oxidation, rust and corrosion inhibition, and haze-free properties. Other objects will be apparent to those skilled in the art.
2. Information Disclosure Statement
U.S. Pat. No. 4,579,673 discloses a rust-inhibited lubricant composition comprising a major amount of grease and a minor amount of a rust inhibitor additive which is the reaction product of a t-alkyl primary amine, a dialkylamine, and maleic anhydride;
Co-assigned U.S. Pat. No. 4,557,848 discloses a novel slow speed marine diesel engine crankcase lubricant characterized by decreased haze and increased corrosion inhibition, where said lubricant comprises a major amount of a mineral lubricating oil and a minor amount of a rust and haze inhibiting additive of the formula ##STR1## wherein R is alkyl, aralkyl, alkaryl, aryl, or cycloalkyl, R' is hydrogen or alkyl, a is 1-10, and b is 1-15;
Co-assigned U.S. Pat. No. 4,536,189 discloses a novel corrosion inhibitor which is the reaction product of maleic anhydride, a hydrocarbon-substituted mono primary amine or ether amine, and a heterocyclic compound which may be either benzotriazole or 5-amino-1,3,4,-thiadiazole-2-thiol, and motor fuels containing said novel corrosion inhibitors;
Co-assigned U.S. Pat. No. 4,464,276 describes the preparation of novel polyoxyalkylene polyamine-triazole complexes and their use in diesel lubricant compositions as antioxidants and corrosion-inhibitors;
U.S. Pat. No. 4,326,987 discloses a rust and corrosion inhibitor useful in petroleum products which is the reaction product of an alkenyl or alkyl succinic acid/anhydride and an alkyl ether diamine;
U.S. Pat. No. 4,282,008 describes a novel corrosion-inhibited fuel composition comprising gasoline, methanol or ethanol, and a minor amount of a corrosion inhibitor which is the reaction product of isatoic anhydride, a C.sub.3 -C.sub.12 poly-primary amine, and an aminotriazole;
API Chemical Products Abstract, Vol. 84, para. 84-50741 (Feb. 20, 1984) describes South African Pat. No. ZA 8208904 which discloses the use of the reaction product of various aliphatic dicarboxylic compounds with various amide compounds as an additive for reducing the cloud point of middle distillates;
API Petroleum and Specialty Products Abstract, Vol. 84, para. 84-20587 (Mar. 5, 1984) describes German Pat. No. DE 3320720 which discloses the use of the reaction product of a vinyl acetate--unsaturated dicarboxylic acid compound copolymer with at least one primary amine--containing compound as an additive for corrosion inhibition and cloud point induction in middle distillates;
API Petroleum and Specialty Products Abstract, Vol. 83, para. 83-21009 (May 2, 1983) describes Eur. Pat. No. EP 71513 which discloses the use of the reaction product of a dicarboxylic acid anhydride and a primary amine-containing compound as an additive for corrosion inhibition and cloud point reduction in middle distillates; and
API Primary Petroleum Products Abstract, Vol. 81, para. 81-22055 (Nov. 23, 1981) describes Eur. Pat. No. EP 34968 which discloses the use of the reaction product of maleic anhydride, an oxyalkylated alcohol and hydrocarbyl amine as a detergent and antirust additive for motor fuels.